Pravda A. The physico-chemical regularities of various additives influence on the discharge-ionization of Copper in low-concentrated nitrate solution

The results of the author's study of the influence of various additives on the process of copper discharge-ionizationin low-concentrated nitrate solutions are presented. The mechanism of copper electrodeposition from a low-concentrated nitrate solution containing no additives was revealed. It has been shown that copper coatings obtained in such conditions contain inclusions of NO3-, NO2-and NH4+ ions. The physico-chemical background for the production of the copper coatings with predetermined characteristics was developed. It was elucidated that for obtaining high quality matt copper coating NO3- ions should be displaced out of the double electric layer, while as for obtaining glossy copper coating the metal deposition should occur at the presence of definite amount of NO3- ions. The formal classification of the investigated additive compounds into two distinct groups by their effect on the side reaction of NO3- ions reduction was proposed. The ionic composition of nitrate solution containing additives was investigated at equilibrium and at its electrolyses. It was found as well, that the important requirement for obtaining the glossy copper coatings from nitrate solutions containing additives of the secondgroup is the inclusion of given additives' copper complexes with participation of NH4+ ions, appeared in solution as a result of NO3-ions reduction. The kinetics and mechanism of electroreduction of copper (II) inlow-concentrated nitrate solution in the presence of additives of different nature were studied. The superficial interactions between inorganic additives and carboxylic acidі with Cu2+ were revealed. It was proved that Trilon B copper (II) complexes are being formed in the bulk nitrate solution.